[Bubba Ho-Tep]

Excuse me typo, the tariff frenzy was in the decades AFTER the Civil War.

But the Republicans only controlled Congress until 1876. From then until 1892, the Democrats controlled it, with a two year exception.

[spacecowboynj]

Ahem: "In Congress, the party passed major legislation to promote rapid modernization, including a national banking system, high tariffs, an income tax, many excise taxes, paper money issued without backing ("greenbacks"), a huge national debt, homestead laws, and aid to education and agriculture."

From 1877-1890:

As the Northern post-bellum economy boomed with heavy and light industry, railroads, mines, and fast-growing cities, as well as prosperous agriculture, the Republicans took credit and promoted policies to keep the fast growth going. They supported big business generally, hard money (i.e. the gold standard), high tariffs, and high pensions for Union veterans. By 1890, however, the Republicans had agreed to the Sherman Anti-Trust Act and the Interstate Commerce Commission in response to complaints from owners of small businesses and farmers. The high McKinley Tariff of 1890 hurt the party and the Democrats swept to a landslide in the off-year elections, even defeating McKinley himself.

SOURCE - Wikipedia

They were the TAX AND SPEND PARTY FOLKS! The party didn't split over the issue until around Teddy Roosevelt!